Oh , seems like i know this caramel, caramel class IV? :D
This is additional information :
1. In Final products --> You need to consider batch size, if you produce many products in 1 batch, you need to do more sampling, you can refer to ISO 2859-1 for optimum sampling size for certain batch size. Do this once for validation,,, but don't forget to re-validate if there are any changes in your production process or formulas.
2. Other possible cross contaminated area --> You need to do this if you also produce other products that do not contain sulfites. You can try allergen swab in those potential cross contamination area ( mixing tank for example ). The purpose of this validation is to ensure that your cleaning procedure is effective.
3. Allergen management programs --> No 1 and no 2 are part of allergen management programs, you also need to consider other area such as segregation in warehouse, production schedule arrangement and so on.
I think it should be OK as long as your allergen management program is effective :D